Well, I will stay with my professional opinion and say it is a "series connected switch"....
No matter what anybody else says it could be a "micro switch".
It could be a secondary switch for "auto-Off" when tape ends or lid is put on.....
So, I'll stick with my professional opinion!
And if you folks think this reel-to-reel audio tape recorder is complicated, take a close look at a vintage computer reel-to-reel tape drive peripheral with vacuum columns to control tape tension. Those puppies could spin up a nine-inch reel of tape to warp speed in a fraction of a second and then stop it on a dime, going forwards or backwards. And they could do this all day and all night without breaking or stretching the tape! Marvelous piece of technology. The first random-access mass storage technology, albeit a tad slow if the data you needed was on opposite ends of the tape.
The image below was part of a restoration team effort in 2008. Details here.